Method of delivering a medical device across a valve

ABSTRACT

Devices and methods for treating veins and venous conditions, such as chronic cerebrospinal venous insufficiency, are provided. In one aspect, the disclosed subject matter provides an intraluminal scaffold having a generally tubular body with a lumen defined therethrough, the tubular body having a compressed condition for delivery and an expanded condition for implant within a vessel having a distended portion, at least a length of the tubular body configured to form an enlarged portion in the expanded condition to engage a wall of the distended portion of the vessel. Methods for fabricating and using the scaffold, methods for remodeling a vein, and methods of deploying a medical device in a vessel without negatively impacting the function of a valve of the vessel, are also provided.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority from U.S. ProvisionalApplication Ser. No. 61/324,031, filed Apr. 14, 2010, which isincorporated by reference in its entirety.

BACKGROUND

1. Technical Field

This disclosed subject matter generally relates to devices and methodsfor treating veins and conditions related to veins. More particularly,the disclosed subject matter relates to devices and methods that areuseful for treating venous anatomies to improve venous sufficiency,

2. Description of Background

Multiple Sclerosis (MS) is a debilitating disease in which the myelinsurrounding the nerves is damaged, resulting in inhibition of nervecommunication and impairment of physical and cognitive abilities. Thereis currently no cure for MS, but management of the disease has beenadvanced through the use of medical treatments, diet, and othernon-surgical means. These treatments reflect the lack of a known causeof MS. MS sufferers apparently have a high prevalence of narrowing,twisting, or blockage of the veins that remove blood from the mainextracranial cerebrospinal veins, the jugular, and the azygous venoussystems. These abnormalities cause blood “refluxing”, or retrogradeflow, which creates reflux in the central nervous system. As a result,pooling of non-oxygenated blood can occur along with pericapillary irondeposition. Since iron is known to create free radicals that are toxicto cells, it is hypothesized that the MS inflammations may be caused bythese iron deposits as seen in CVD, mentioned above. The high ironcontent of MS patients' brains has been confirmed. The work led to thecoining of the venous disorder Chronic Cerebrospinal VenousInsufficiency (CCSVI).

Veins are thin structures that lack some of the muscular features ofarteries. Thus, distension of the veins is common. In the internaljugular vein, MS sufferers can develop distension and bulging as shownin FIG. 1. These bulbs can expand, or the entire length of vessel, or asubstantial portion thereof, may expand, which causes blood accumulationand reflux as described above. Further, the venous system, andparticularly the jugular portion of the venous system, includes valvesthat operate to allow blood to flow easily in one direction but resistthe backflow of blood in the opposite direction. Veins can distend nearthe venous valves, and this distention can occur on either side of tilevalve. For example, the vein may have a barbell shape with the valve inthe handle area. Thus, the valve can act as a stenosis that restrictsblood now in both directions and thereby inhibits now. Poor venousdrainage and the resulting deposition of iron may be a primary orsecondary cause of other diseases as well. For example, beyond MS, thetreatment of CCSVI can also help prevent or treat dementia, Alzheimer'sdisease, or other diseases of the central nervous system.

There is a need for a method that can be used to reduce the bulbs ordistensions within a vein in order to reduce reflux and bloodaccumulation and thereby treat an underlying disease. There is also aneed to maintain a venous valve open since blood now through the jugularveins can be beneficial, particularly in preventing pooling of blood inthe brain.

Stenting is one option for treating CCSVI because a stent placed in theanatomy would eliminate the narrowing, twisting, or blockage of theveins, and thus prevent refluxing by allowing normal drainage of bloodfrom the brain. Traditionally, cylindrical stents have been used in thetreatment of vascular disease. That is, stents in their as-cutconfiguration are traditionally cylindrical. The reason for this isessentially twofold. First, the cost of manufacturing a non-cylindricalstent is substantially higher using traditional processes, and second,there has not been a strong demand for non-cylindrical stents since mostdiseased vessels are essentially cylindrical, and any anatomicaldeviations can be compensated for through balloon deployment andtouch-up. However, there are no stents available on the market that aresized or designed for treating the vessel conditions relevant to CCSVIand the use of cylindrical stents to do so may not be fruitful.

Stenting abnormal vessel segments with traditional cylindrical stentshas at least two downfalls. First, such stents have a tendency todislodge from the vein because the veins have low radial force and arerelatively large compared to typical stent diameters. When this happens,the stent may flow downstream and cause risk to the patient if it entersthe heart, another organ, or otherwise disrupts blood flow, for example.Second, a stent with a cylindrical profile may not conform fully to abulbous vein, and there may therefore be poor scaffolding andopportunity for thrombus formation in the gaps between the vein wall andthe stent. Thus, there is a need for a stent that can be deployed withinnon-cylindrical vessel segments that provides the advantages of goodvessel conformity in unusual anatomies, and that can produce ananchoring effect within a vein to prevent stent loss.

For many of the devices that may be used for the treatment of CCSVI,access to and delivery within the jugular vein may be necessary.However, as shown in FIG. 2, even basic access to a jugular can bedifficult to accomplish without damaging the venous valves. As shown,the venous valves are formed by valve leaflets which are very thinstructures that tend to protrude and taper in the antegrade direction.However, since access to the patient anatomy during interventionalprocedures is commonly made in the radial or femoral region, a guidewirewill normally be passed in the retrograde direction. Therefore, as theguidewire is passed into the vein, it may tend to catch the valveleaflets and press against them in a resistive manner. Due to therelative weakness of the leaflets, they may tear or be otherwisedamages. If the leaflets tear, they may be unable to resist backflow andtherefore their function will be destroyed. This same problem can occurwhen other devices, such as balloon catheters or other catheter devices,are passed in the same direction as the guidewire. Thus, there is a needfor a method and system of accessing the jugular veins that willeliminate or minimize the risk of damaging the valve leaflets.

SUMMARY

The purpose and advantages of the disclosed subject matter will bedescribed and apparent from the description that follows, and throughthe practice of the disclosed subject matter. This devices and methodsdisclosed herein can apply to treatment of various venous conditions,including CCSVI.

In accordance with one aspect of the present application, anintraluminal scaffold is provided. The intraluminal scaffold has agenerally tubular body with a lumen defined therethrough, the tubularbody having a compressed condition for delivery and an expandedcondition for implant within a vessel having a distended portion. Atleast a length of the tubular body is configured to form an enlargedportion in the expanded condition to engage a wall of the distendedportion of the vessel. As an example, the enlarged portion can have anon-cylindrical shape.

In some embodiments of the intraluminal scaffold, the enlarged portionhas a barrel shape. In some embodiments, the enlarged portion of thetubular body includes a pattern of cells substantially uniform in sizewhen the scaffold is in the expanded condition. The non-cylindricalshaped portion can be formed of a continuous curved strut. In otherembodiments, the enlarged portion can have a shape selected from abuttercup shape, a bulbous shape, an hourglass shape, a dumbbell shape,a tapered shape, a flared shape, and a corrugated shape. In oneparticular embodiment, the enlarged portion includes a spiral-shapedwire. In certain embodiments, the enlarged portion of the tubular bodyin the expanded condition conforms to the wall of the distended portionof the vessel.

The intraluminal scaffold can be a conforming scaffold, a supportingscaffold, or include one or more portions that either conform or supporta vessel in which it is implanted. The scaffold can be balloonexpandable, self-expandable or a portion of the scaffold is balloonexpandable and the other portion of the scaffold is self-expandable.

In some embodiments, the tubular body of the intraluminal scaffoldfurther comprises a cylindrical portion in the expanded conditionextending from at least one end of the enlarged portion of the tubularbody. The enlarged portion in the expanded condition can have a profilelarger than a diameter of the cylindrical portion in the expandedcondition. The enlarged portion can be disposed at an end of thescaffold. The intraluminal scaffold can further include a secondcylindrical portion extending from a second end of the enlarged portion.

In some embodiments, the enlarged portion of the intraluminal scaffoldincludes a bistable construction. The enlarged portion, including thebistable construction, in the expanded condition can have a profilelarger than a diameter of the cylindrical portion in the expandedcondition. The enlarged portion also can have sufficient flexibility toconform to the distended portion of the vessel without plasticdeformation.

In some embodiments, at least a portion of the tubular member of theintraluminal scaffold is formed of a material selected from a polymericmaterial, a metallic material, and a shape-memory material. In certainembodiments, the cylindrical portion of the intraluminal scaffold isformed of a material different than the enlarged portion. For example,the cylindrical portion can be formed from a material that plasticallydeforms when expanded to the expanded condition. In certain embodiments,the scaffold is made of a degradable material, for example, a materialthat is capable of extravascular degradation.

In certain embodiments, the tubular body of the intraluminal scaffoldincludes a side opening defined therein. The tubular body can furtherinclude a side branch in communication with the side opening toaccommodate a vessel bifurcation.

In one embodiment, the intraluminal scaffold includes a restraining bandto induce formation of the non-cylindrical shape when expanded to theexpanded condition. The restraining band can have recoil, and can beformed of a degradable material.

In some embodiments, the tubular body of the intraluminal scaffoldconforms to the wall of the vessel during vessel relaxation due toadjustments in fluid flow.

In some embodiments, the tubular body of the intraluminal scaffoldrecoils from its initial expanded condition over a period of timegreater than one day. For example, the recoil can from its initialexpanded condition can result from degradation of the material of thescaffold, e.g., a degradable material.

The intraluminal scaffold can further include a therapeutic substance.The therapeutic substance can include any one or more of the therapeuticsubstances described in the Detailed

Description below , and in particular, one or more of fondaparinux(Arixtra®), Enoxaparin, Bivaliruden, a factor Xa inhibitor, acollagenase (e.g., Xiaflex®), or endopeptidase.

The intraluminal scaffold can further include an integrated filtersystem.

In accordance with another aspect of the disclosed subject matter, amethod of treating a condition of a vessel is provided. According to themethod, an intraluminal scaffold is provided, which includes a generallytubular body with a lumen defined therethrough, the tubular body havinga compressed condition for delivery and an expanded condition forimplant within a vessel having a distended portion, at least a length ofthe tubular body configured to form an enlarged portion in the expandedcondition. The intraluminal scaffold is deployed within a distendedportion of a vessel with the enlarged portion of the scaffold engaging awall of the distended portion of the vessel.

As disclosed, the scaffold is deployed in a vein, such as an internaljugular vein. The scaffold can have a length greater than the diameterof the brachiocephalic vein. The vein can have or is subject to a valveanomaly. The tubular body of the scaffold can conform to the wall of thevessel during vessel relaxation due to adjustments in fluid flow.

In some embodiments of the method, the deployed scaffold is allowed tomigrate in or adhere to the wall of the vessel. Further, the tubularbody of the scaffold recoils from its initial expanded condition afterthe scaffold migrate in or adheres to the wall of the vessel. Thetubular member can be formed of a degradable material. In theseembodiments, the tubular member can recoil from its initial expandedcondition due to degradation of the degradable material.

In accordance with yet another aspect of the disclosed subject matter, amethod of treating a condition of a vessel is provided. The methodincludes: providing an intraluminal scaffold comprising a generallytubular body with a lumen defined therethrough, the tubular body havinga compressed condition for delivery and an expanded condition forimplant within a vessel subject to a valve anomaly; deploying thescaffold within the vessel; and allowing the tubular body of thescaffold to conform to a wall of the vessel.

In some embodiments, the above method further includes allowing thescaffold to migrate in or adhere to the wall of the vessel, and canfurther include allowing the tubular body of the scaffold to recoil fromits initial expanded condition after the scaffold migrates in or adheresto the wall of the vessel. The recoil can be resulting from degradationof the material of the scaffold if the material is degradable. Where thescaffold is made of a degradable material, the method can furtherinclude allowing the tubular body to migrate through the wall of vesselfor extravascular degradation thereof.

In some embodiments of the above method, the scaffold is deployed in avein, such as an internal jugular vein. The tubular body of the scaffoldcan conform to the wall of the vessel during vessel relaxation due toadjustments in fluid flow. Additionally or alternatively, the vessel canhave a distended portion, and at least a length of the tubular body isconfigured to form an enlarged portion in the expanded condition. Inthese embodiments, deploying the scaffold can include engaging theenlarged portion of the scaffold with the wall of the distended portionof the vessel.

In accordance with a further aspect of the disclosed subject matter, amethod of treating a condition of a vessel is provided selecting apatient demonstrating a symptom associated with a condition selectedfrom fatigue, chronic fatigue, venous insufficiency of the leg, chronicvenous insufficiency, deep vein thrombosis, Alzheimers, adult onsetdementia, Parkinsons, May-Thurner, Budd-Chiari, CCSVI, and MS, anddeploying an intraluminal scaffold in a vein having or subject to avalve anomaly believed to be associated with the symptom. For example,the scaffold can be deployed in a vein having one or more valves, suchas veins having valves which are atypical or irregular in function orotherwise insufficient. Such valves can be associated with a neck (e.g.,jugular), a leg, or a liver. As a particular example, the vein can be aninternal jugular vein.

In accordance with yet another aspect of the disclosed subject matter,an intraluminal scaffold is provided. The scaffold includes a firstannular element radially expandable with respect to a longitudinal axisdefined therethrough, a second annular element radially expandable withrespect to the longitudinal axis, and at least one axial strutconnecting the first annular element and the second annular element. Theat least one axial strut has sufficient flexibility to conform to a wallof a distended portion of a vessel.

In some embodiments of the above scaffold, the at least one axial struthas sufficient flexibility to conform to the distended portion of thevessel without plastic deformation. In other embodiments, at least oneof the first annular element and the second annular element isplastically deformed when radially expanded. In other embodiments, theat least one axial strut is self-expandable, and at least one of thefirst annular element and the second annular element isballoon-expandable. In other embodiments, the at least one axial strutand at least one of the first and second annular elements are eachself-expandable. In certain embodiments, the at least one axial strut ismade of a material in its austenitic phase and at least one of the firstannular element and second annular element is made of a material in itsmartensitic phase. The at least one axial strut can be made of a polymermaterial. In other embodiments, the at least one axial strut is made ofa linear elastic material.

In some embodiments, the first annular element has a different diameterthan the second annular element when in the expanded condition. In someembodiments, the first annular element or the second annular element caninclude a meandering pattern, such as a sinusoidal ring.

In some embodiments, the at least one axial strut defines a radiallyoutward strength lower than that of the first annular element or thesecond annular element.

In some embodiments, the at least one axial strut includes a pluralityof axial struts. In these embodiments, the scaffold can further includeat least one radial connector disposed between and connecting a selectedpair of circumferentially adjacent axial struts. The plurality of axialstruts can form a bulbous shape when expanded.

In accordance with another aspect of the disclosed subject matter, amethod of fabricating an intraluminal scaffold is provided. The methodincludes providing a tubular body with a lumen defined therethrough, atleast a length of the tubular body configured to form an enlargedportion, and defining a plurality of cells in the tubular body to forman intraluminal scaffold capable of having a compressed condition fordelivery and an expanded condition for implant within a vessel, the atleast a length of the tubular body having the enlarged portion when inthe expanded condition.

In one embodiment of the fabrication method, providing the tubular bodyincludes extruding a generally cylindrical tube and expanding at least aportion of the cylindrical tube to form the enlarged portion. In oneembodiment, expanding at least the portion of the cylindrical tubeincludes blow molding to form the enlarged portion. In anotherembodiment, expanding at least the portion of the cylindrical tubeincludes hydroforming the enlarged portion.

In some embodiments, the tubular body is made of a polymeric material.Alternatively, the tubular body material can include a metal or a metalalloy.

In some embodiments, providing the tubular body includes depositingtubular body material on a mandrel having a surface defining theenlarged portion. In other embodiments, defining the plurality of cellsin the tubular body includes depositing the tubular body material onselect locations of the surface of the mandrel. In yet otherembodiments, defining the plurality of cells in the tubular bodyincludes removing material from the tubular body, e.g., laser cuttingthe tubular body.

In some embodiments, the plurality of cells are uniform in size andshape. In other embodiments, the plurality of cells are nonuniform insize or shape.

In accordance with another aspect of the disclosed subject matter, amethod of deploying a medical device is provided. The method includes:establishing an open condition of a valve in a vessel of a patient;moving a medical device through the opened valve; and deploying themedical device at a target site, wherein establishing the opencondition, moving the medical device and deploying the medical deviceare completed without negatively impacting the function of the valve.

In the above method of deploying the medical device, establishing theopen condition of the valve can include altering fluid flow through thevessel in the vicinity of the valve. For example, a fluid can beintroduced in an antegrade direction from a location upstream of thevalve to induce opening of the valve. Before introducing the fluid, thevessel can be occluded at a location upstream of the valve.Alternatively, the fluid flow can be drawn in an antegrade direction,for example, by providing suction at a location downstream of the valve,to open the valve. In either case, the medical device can be moved froma retrograde direction through the opened valve from a locationdownstream of the valve. In other embodiments, altering fluid flow inthe vicinity of the valve includes occluding at least one body lumenproximal to and fluidly coupled with the vessel to increase antegradeflow across the valve.

Alternatively, establishing the open condition of the valve includestemporarily expanding an expandable cuff within the valve withoutpermanently impacting the function of the valve.

In some embodiments, deploying the medical device includes using acatheter, and the method further include removing the catheter afterdeploying the medical device. The medical device can be an intraluminalscaffold. Further, the intraluminal scaffold can have a generallytubular body with a lumen defined therethrough, the tubular body havinga compressed condition for delivery and an expanded condition forimplant within the vessel, at least a length of the tubular bodyconfigured to form an enlarged portion in the expanded condition.

In some embodiments, the valve is a venous valve. The venous valve canbe located in one of an internal jugular vein and an external jugularvein.

In accordance with another aspect of the disclosed subject matter, amethod of deploying a medical device across a plurality of valves of avessel of a patient is provided. A catheter is provided which has aninner shaft member and an outer shaft member co-axially disposed andaxially moveable relative to each other. The catheter is positioned in avessel having a plurality of valves including a first valve and a secondvalve. A distal end of the outer shaft member is advanced across thefirst valve without permanently impacting the function of the firstvalve; moving the inner shaft member axially relative to the outer shaftmember; and advancing a distal end of the inner shaft member across thesecond valve without permanently impacting the function of the secondvalve.

In some embodiments of the above method, the distal end of at least oneof the inner shaft member and the outer shaft member is formed with anatraumatic configuration.

In some embodiments, the method further includes delivering a medicaldevice through the inner shaft member to a target site. The medicaldevice can be an intraluminal scaffold. The scaffold can have agenerally tubular body with a lumen defined therethrough, the tubularbody having a compressed condition for delivery and an expandedcondition for implant within the vessel, at least a length of thetubular body configured to form an enlarged portion in the expandedcondition.

In some embodiments of the method, the plurality of valves are venousvalves.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further appreciation of the above and other advantages, referenceis made to the following detailed description and to the drawings, inwhich:

FIGS. 1 schematically illustrates the anatomy of the internal jugularvein.

FIG. 2 schematically illustrates a scenario as a catheter is as beingintroduced in a retrograde direction through a valve.

FIGS. 3-5 illustrate intraluminal scaffolds and methods of use thereoffor treating a condition of a vein according to one aspect of thedisclosed subject matter.

FIGS. 6 through 9 illustrate methods of treating a condition of a veinaccording to another aspect of the disclosed subject matter, whereinFIG. 8 depicts a vein demonstrating a vein sac.

FIGS. 10 through 17 illustrate methods of forming an intraluminalscaffold having an enlarged portion according to a further aspect of thedisclosed subject matter.

FIGS. 18 through 22 illustrate a method of treating a condition of avein according to another aspect of the disclosed subject matter.

FIGS. 23 depicts an intraluminal scaffold having an enlargednon-cylindrincal portion according to the disclosed subject matter,

FIG. 24 depicts an exemplary balloon suitable for deploying the stentdepicted in FIG. 23.

FIGS. 25 through 26 illustrate certain embodiments of an intraluminalscaffold having a bistable construction according to one aspect of thedisclosed subject matter.

FIGS. 27 through 37 illustrate various embodiments of an intraluminalscaffold including an enlarged portion according to the disclosedsubject matter.

FIGS. 38 through 41 illustrate various embodiments of an intraluminalscaffold having one or more generally axial struts according to anotheraspect of the disclosed subject matter.

FIGS. 42 through 44 schematically illustrate a catheter device and anassociated method suitable for deploying a medical device across a valveaccording to one aspect of the disclosed subject matter.

FIGS. 45 through 47 illustrate a catheter device and an associatedmethod suitable for deploying a medical device across a valve accordingto another aspect of the disclosed subject matter.

FIGS. 48 through 49 illustrate non-target vessel occlusion to dilatetarget vessel valves according to one embodiment of the disclosedsubject matter.

FIGS. 50 through 51 illustrate a method of accessing veins through theneck according to one embodiment of the disclosed subject matter.

FIGS. 52 through 56 illustrate a telescoping catheter and a method ofuse thereof for deploying a medical device according to one aspect ofthe disclosed subject matter.

FIGS. 57 through 59 illustrate a catheter device having an expandablecuff and the associated method for opening a valve according to oneaspect of the disclosed subject matter.

DETAILED DESCRIPTION

While the disclosed subject matter may be embodied in many differentforms, reference will now be made in detail to specific embodiments ofthe disclosed subject, examples of which are illustrated in theaccompanying drawings. This description is an exemplification of theprinciples of the disclosed subject matter and is not intended to limitthe subject matter to the particular embodiments illustrated.

In accordance with one aspect of the disclosed matter, an intraluminalscaffold is provided which is suitable to be implanted in a body lumen,such as a blood vessel or the like, e.g., a vein, of a patient. Ingeneral, the construction of the intraluminal scaffold can be selectedsuch that the scaffold, or a portion thereof, can either support orconform to a body lumen. By “conforming,” when the term relates to ascaffold of a portion thereof, it is intended that the overall geometryand stiffness of the scaffold, or relevant portion thereof, are suchthat the scaffold (or the portion thereof) can engage the lumen wall toinhibit movement of the scaffold within the lumen under the normal useconditions without substantially altering the diameter of the lumen fromits undisturbed or natural state prior to implanting the scaffold.However, the conforming scaffold can be suitably sized and flexible tomaintain engagement with the vessel wall in response to a change in thediameter of the vessel between its smallest diameter to its maximumanticipated diameter corresponding to different physiological states ofthe patient. The conforming scaffold does not urge or otherwise supportthe lumen wall in a predetermined diameter, but rather dynamicallychanges its shape to adapt to the varying size of the lumen (e.g., ablood vessel) at different anatomical sites and in differentphysiological conditions, and this allows for easy deployment,retrieval, and repositioning of the conforming scaffold within the bloodvessel. In contrast, a supporting scaffold is usually configured formaintaining the patency of a vessel, such as an artery, and is greaterin radial strength and stiffness. The scaffolds disclosed herein can beeither a supporting scaffold or conforming scaffold, or include portionsthat have the characteristics of either a supporting scaffold or aconforming scaffold. Thus, the term “scaffold” encompasses “stent,” andthe two terms are used interchangeably herein. The scaffolds or stentsdescribed herein can include structural patterns used for conventionalstents such as those formed by a series of longitudinally arranged ringsformed by interconnected struts and connected with longitudinalconnectors. However, the structural elements of the scaffolds or stentsof the disclosed matter are not restricted to the struts or connectorsor traditional stents, but likewise include flexible or pliantfilaments, wire, and the like.

Accordingly, one aspect of the disclosed subject matter provides anintraluminal scaffold is provided. The intraluminal scaffold has agenerally tubular body with a lumen defined therethrough, the tubularbody having a compressed condition for delivery and an expandedcondition for implant within a vessel having a distended portion. Atleast a length of the tubular body configured to form an enlargedportion in the expanded condition to engage a wall of the distendedportion of the vessel. In another aspect, the disclosed subject matterprovides a method of treating a condition of a vessel, such as a vein,which includes deploying such a scaffold within a distended portion of avessel such that upon the deployment the enlarged portion engages a wallof the distended portion of the vessel. The enlarged portion can have anon-cylindrical shape. The vessel can be a vein, e.g., an internaljugular vein, wherein the vessel can have or is subject to a valveanomaly (e.g., one or more valves in the vein are malformed ormalfunctional). This method will be described in conjunction with theintraluminal scaffold below, and it is understood the method isgenerally applicable for any of the various embodiments of theintraluminal scaffold described herein.

For illustration and not limitation, various embodiments of theintraluminal scaffold and related delivery systems of the disclosedsubject matter are described below in connection with the drawings. Itis noted that the figures are not to scale and certain dimensions havebeen exaggerated for clarity. Referring to FIG. 3, a stent 100 has adistal end enlarged portion 102 with an increased profile in an expandedcondition (a bulbous portion is depicted for illustration purpose). Thisenlarged non-cylindrical portion can prevent the stent 100 fromdislodging from the vein that it is deployed within. For example, thestent can be positioned within one of the internal jugular veins,wherein bulbous segment of the stent 100 will act to retain the stentwithin the veins. Veins are typically more elastic than arteries andthus may require additional anchoring to keep the stent 100 in place.The closely conforming feature of the stent in accordance with thedisclosed subject matter may reduce thrombus formation within the vein,which may otherwise occur if a gap left between the stent and the vesselwall. The non-cylindrical portion as described herein can be embodied inmany different geometrical configurations, for example thenon-cylindrical portion may be embodied as a flared portion as shown inFIG. 4. Other geometrical configurations contemplated herein may have aconical or tapered appearance, or take other shapes as further describedbelow.

As previously described, veins are more elastic than arteries. Even withthe use of the anchoring techniques, it is possible that the stent couldstill dislodge when used in the venous system. Accordingly, stent 100can be sized and configured to have an expansion profile thatapproximates the average diameter of the target vein and a total lengththat is sufficient to prevent the stent from being dislodged into thebrachiocephalic veins, in the event of stent dislodgment. The stentlength (L) can be at least as long as the diameter (D) of thebrachiocephalic vein at the ostium of the target vein. Alternatively,the stent length can be 2-4 times that diameter. This feature isillustrated further in FIG. 5. For example and not limitation, stent 100can have radial strength tuned to the properties of the target vein.Since the elasticity of the vein is greater, the stent 100 can be aconforming stent rather than a supporting stent.

Access to the target veins that include the most anatomicalabnormalities can be accomplished in a number of manners. In order toaccess the right internal jugular with a larger profile stent, acatheter can be delivered through and tracked the inferior vena cava.Once near the jugular, the catheter can be advanced directly into theright internal jugular vein from the superior vena cava, or it can beadvanced into the left internal jugular via the brachiocephalic vein.Alternatively, when using a small profile stent delivery system, e.g.with a balloon expandable stent, access can be made through thesubclavian vein in the wrist. A delivery catheter can then be tracked tothe right internal jugular vein, or it can be advanced into the leftinternal jugular vein via the brachiocephalic vein.

The stent 100 can be formed from various materials. For example, thestent 100 can be formed of a balloon expandable material such asstainless steel, silver, platinum, tantalum, palladium, cobalt-chromiumalloys such as L605, MP35N, or MP2ON, niobium, iridium, any equivalentsthereof, alloys thereof, and combinations thereof Alternatively, it canbe a self-expandable stent material such as nickel-titanium,copper-zinc-aluminum, or copper-aluminum-nickel. In addition, thematerial can be a shape memory material, a polymeric material, adegradable material, e.g., a biodegradable material, a resorbablematerial, and the like. Further, different portions of the stent can beformed of different material.

The material can be selected according to target anatomy. If the targetanatomy has a large diameter, it may be preferable to use aself-expanding stent that can accommodate large vessels. However,smaller veins may benefit more from balloon expandable stents. Also,considerations such as the target vessel elasticity can be taken intoaccount. In cases where the vessel is more elastic, it may be preferableto use a self expanding stent, and vice versa.

In an alternative embodiment, the stent may have an integrated filtersystem. For example, a parachute basket can be attached to one or morestent rings such that deployment of the stent within a vein will causethe basket to canopy across the vein. Therefore, any thrombotic materialthat is dislodged during placement would travel into the basket and becaptured, thereby preventing a thrombotic event. Alternatively, anembolic protection device may be used during stent deployment to captureany acute thrombus and remove it from the body following stentplacement.

As described above, the enlarged portion of the stent can be use as ananchor to retain the stent within a body lumen, e.g., a vein. Asillustrated in FIG. 27, the desired anchor point when treating CCSVI canbe near the bulbous segment in the proximal area of the internal jugularvein. It will be appreciated that this location is selected forillustrative purpose only, and the stent can be positioned elsewhere.

As illustrated in FIG. 28, the enlarged portion can include aspiral-shaped element 172 used as an anchor to stabilize a stent 170within a vein. An advantage of a spiral anchor is its ability to conformto a wide range of vessels without exerting excessive radial load to thevessel wall. The stent embodiment may include one portion 174 thatcomprises one or more typical stent rings 176. That is, the portion 174can include a generally meandering stent ring pattern connected withadjacent stent rings. This portion 174 of the stent 170 can bepositioned within the distal segment of the vein beyond the desiredanchor point. The stent 170 will then be anchored in place by the spiralanchor 172 segment that is intended to be positioned within the bulboussegment of the vein. The spiral anchor 172 can be formed by one or morespiral elements 178 that extend in a proximal direction from the normalstent segment 174. The spiral segment(s) 178 may gradually increase indiameter, thereby ensuring that they will remain in contact with thedistended vessel and anchor the stent 170 within the vessel.

In an alternative embodiment, multiple spiral anchor segments 172 can beused to provide greater apposition with the vessel and therefore betteranchoring. The multiple spiral anchors 172 can be connected with oneanother, for example by attaching the spirals at their ends.Alternatively, they can be completely independent from one another. Thespirals can be formed from the same tubing as the normal stent segment,or they can be formed separately and then added to the stent segment 174through the use of welding or other bonding processes.

As shown in FIG. 36, a spiral anchor 240 having a bulbous profile can beused to anchor the stent 242 more particularly within a bulbous veinsegment. One or more spiral anchors 240 can extend from the end 244 ofthe stent 242 and be formed in a spiral or curvilinear manner that firstexpands in diameter and then reduces in diameter. Thus, the spiralanchor 240 will conform to a bulbous segment of a vein.

Referring to FIG. 29A, the enlarged portion of the stent can be abulbous anchor 180 to secure the stent 182 within a vein. The bulbousanchor can have a generally barrel shaped profile as depicted. Thebarrel shape can be the result of a shape memory effect introducedduring stent manufacturing, or it can be the result of expansion by abarrel-shaped balloon. In either case, the stent design can provide thatupon expansion, the individual cell area is approximately equivalent oruniform throughout the stent structure. In other words, even thoughindividual rings across the stent structure have varying diameters, theintracellular area remains unaffected and therefore the vascularscaffolding is more consistent than would be the case if a typical stentdesign were deployed into a barrel shape. Further more, use of abarrel-shaped stent with more uniform cellular structure will providemore consistent radial strength over the stent length.

As shown in FIG. 29B, the stent can be particularly useful in thetreatment of veins that are bulged or distended. This distension canoccur, for example, near a venous valve. This is particularly true whenthe patient presents with venous insufficiency. It is notable that thebulging of the veins can be immediately adjacent to the valve, or thevalve can be within the bulbous region. Often, the valve is stenosed andclosed under these circumstances. Thus, in a method of using the stent(or any of the other stents described herein), the stent can be placedacross the valve, wherein the stent may be placed across the valve wherethe stent is placed in only the distended region, or, in both thedistended region and the valve segment.

Referring to FIG. 29C, in an alternative embodiment the stent caninclude only one, or very few, stent rings 290. In addition, the stentring itself can be formed with a barrel shape. Therefore, eachindividual strut can be curved in a way that creates annulus having abarrel shape. The length of the struts can be varied depending on thedesign to produce a stent that is longer or shorter, for example.Deployment of a stent structure such as the one illustrated in FIG. 29Cwithin a vessel can conform to or support a distended region with lowerrisk of dislodgment.

As shown in FIG. 30, the enlarged portion can include buttercup anchorfor securing the stent 190 within a vein. The buttercup designcontemplates that a segment 192 of the stent will be tapered outward.This flared portion 192 will have a larger profile or diameter (D) ascompared to the diameter (d) of the normal stent segment 194. Thisstructure creates an anchor that resists movement in at least two ways.First, the larger diameter D formed by the outwardly extending struts ofthe stent 190 is intended to provide some frictional load against thevein wall that resists dislodgment. Second, since the flared portionprojects in a certain direction, it will preferentially resist motionbecause the flares will engage the tissue wall and expand even furtherif moved in the direction of the flare expansion.

FIGS. 31 and 32 illustrate a stent where the non-cylindrical shapedportion can include a branched portion. The branched portion can beformed by one or more annular rings of the stent protruding outward fromthe branch location forming a surface irregularity, or by a side branchin communication with a side opening of the stent. The branched portioncan engage a vessel bifurcation in order to prevent stent dislodgment.FIG. 31 indicates an exemplary anatomy in the region of the internaljugular vein. There can be one or more collaterals or side branch veinsthat parallel the internal jugular vein. As shown in FIG. 32, thesebranches allow a stent 200 to be used with side branch segments 202 thatcan engage the collaterals. Once these collaterals are engaged, it ismore difficult for the stent to dislodge because the dislodgment forceexerted on the stent by the blood flow is resisted by the reaction forcethat the side branch vessels apply to the stent. Thus, the stent 202 issubstantially more secure within the vein.

FIG. 33 shows a stent 210 showing a braided stent design that utilizes arestraining band 212 to produce a compressive load on the stentstructure following deployment. This compressive load induces theformation of a bulging of the stent that creates an anchor point in thevessel. The restraining band 212 can be fabricated from an elastomericmaterial and bonded to the ends 214 and 216 of the stent 210 using athermal or chemical bond. Alternatively, the band 212 can bemechanically restrained by inserting it and heat staking it within agroove or hole (not shown on FIG. 33) within the stent 210. In order toprevent the stent 210 from expanding prior to deployment, the stent canbe delivered from a constraining tube, such as those used forself-expandable stents. Once deployed from the tube, the band 212 can bereleased and allowed to recoil and compress the stent to form thedesired non-cylindrical shape. The band can also be made of a degradableor resorbable material, which can weaken over time to allow the stent torecoil to a smaller profile.

As shown in FIG. 34, a dumbbell shaped stent 220 can be used to anchorwithin a vein. In this embodiment, the stent can be cut from tubing witha non-cylindrical form, or alternatively, the stent can be formed from acylindrical tube that is subsequently formed into a dumbbell shapethrough heat treating or mechanical strain processes. These methods ofmanufacturing a stent bulge will be further discussed below.

Referring to FIG. 35, stabilization of the stent can be facilitatedthrough the use of an hourglass anchor design. Like the dumbbell designabove, an hourglass shaped stent 230 may also be formed fromnon-cylindrical tubing. However, only the ends 232 and 234 of the stentneed be tapered, thus it can be easier to form the tapers after stentcutting than it is to form bulbous segments. This is because the taperscan be formed simply by advancing the stent over a taper and introducingsufficient heat or stress to cause the portion to heat set to the newshape.

FIG. 37 shows that a stent 250 having a or a corrugated shape, e.g., a“pine cone” profile can be used to secure a stent within a vein. Thispine cone shape can be formed by producing a stent with varying ringexpansion diameters 252 and 254. The varying stent ring diameter can beaccomplished through the use of shape memory metals, e.g. Nitinol, inwhich the rings are heat set to the desired pine cone shape.Alternatively, a specialized delivery system can be used with anon-cylindrical balloon wherein the balloon has an undulating surfacethat expands the individual stent rings to varying diameters.

Referring to FIG. 23, a bulbous stent profile is shown. It will beappreciated that one way to expand a bulbous stent 150 is to use abulbous balloon 154 such as the one shown in FIG. 24.

If a balloon such as the one shown in FIG. 24 is used with a deformablestent, it would naturally cause a larger profile in the stent segmentthat is located over the bulbous balloon section 156. This segment wouldthen provide anchoring within a vein. However, this approach has atleast two disadvantages because the production of a bulbous balloon 154is challenging, given that special molds and processes need to beproduced and because molding a balloon in this shape would create anespecially weak balloon wall in the bulbous section 156, which is proneto failure. Secondly, even if the bulbous balloon section 156 issuccessfully formed, it would not necessarily expand the stent 150 in amanner that will conform well to the vessel or produce a beneficialanchoring. This is due to the natural recoil in deformable stents thatwould be amplified in the case of a non-cylindrical expansion profile.

In some embodiments, the non-cylindrical shaped portion can include abistable construction. According to this embodiment and referring toFIG. 25, a stent 150 has at least one portion 158 that comprises abistable stent pattern. This portion 158 is referred to as a bistableportion 158, as it has two stable positions: a low profile position(e.g., a generally cylindrical configuration) and a high profileposition. The stent pattern is able to flex between these positions dueto the arcuate shaped elements 160 that can bend back and forth withlittle or no plastic deformation along their length.

Due to the bistable characteristics of the bistable portion 158, it canhave an expanded bulbous profile when the arcuate shaped elements 160are expanded to a significantly larger profile than the expansiondiameter of adjacent portions. The adjacent portions 162 and 164 can beconventional meandering stent pattern portions, or any other stentpattern that is of the typical plastically deformable variety. Thus,expansion of the adjacent portions 162 and 164 can be obtained byinflating a balloon rather than on any type of bistable characteristic.

As shown in FIG. 26, the stent 150 can be crimped onto a typical ballooncatheter 166 in preparation for delivery. The portions formed fromballoon deformable stent patterns can be crimped to a low profile byintroducing plastic deformation into the stent struts and crowns. Thebistable portion 158 can be crimped to a smaller diameter by forcing thearcuate shaped elements 160 to its low profile configuration. It will beappreciated that much of the bistable portion 158 is not plasticallydeformed when in this crimped position, but that the bistable portion158 will nonetheless retain its low profile until it is expanded by aballoon element 168.

Delivery of the stent device 150 into the target vein 170 can beaccomplished using standard interventional techniques. The stentdelivery system can be tracked over a guidewire (not shown) to thetarget anatomy, at which point the balloon 168 can be expanded using aninflation medium such as contrast or saline. As the balloon inflates, itwill expand the deformable stent portions 162 and 164 against the vesselwall. Likewise, the bistable portion 158 will expand automaticallytoward a high profile after the arcuate shaped elements are urged past athreshold diameter. Thus, the expansion of the bistable portion 158 willproduce a bulbous stent segment with a larger profile without the needfor specialized balloon shapes for deployment.

Expansion of the bistable portion 150 can be located within a distendedportion of the vessel such that adequate apposition of a distendedvessel is achieved. Furthermore, the bistable portion 158 at theexpanded configuration can produce an interference with the vessel wallthat provides positive anchoring of the stent 150 within the targetvessel. The bistable portion can have sufficient flexibility to conformto the distended portion of the vessel without plastic deformation.

The stent having a bistable portion as described above can be fabricatedfrom a number of well known medical device materials. For example, itcan be formed from self-expandable materials, e.g. nickel-titaniumalloy, plastically deformable materials, e.g. stainless steel orcobalt-chromium alloys, or degradable materials, e.g. PLLA. It will beappreciated that each of these classes of materials encompasses manyother materials that would also be suitable.

It is appreciated that although the various embodiments of the stents asdescribed above have been described above as a balloon expandable,. theycan also be self-expandable or at least in a hybrid variation in whichthe stent is self-expandable in a selected portion (e.g., the enlargedportion), or have a degree of self-expandable characteristics given thatit is fabricated from a self-expanding material, but that its expansionis initially onset by the inflation of a balloon element that it isdisposed upon.

In accordance with another aspect of the disclosed subject matter, amethod of treating a condition of a vessel is provided. The methodincludes providing an intraluminal scaffold comprising a generallytubular body with a lumen defined therethrough, the tubular body havinga compressed condition for delivery and an expanded condition forimplant within a vessel having a distended portion, at least a length ofthe tubular body configured to form an enlarged portion in the expandedcondition; and deploying the scaffold within a distended portion of avessel with the enlarged portion of the scaffold engaging a wall of thedistended portion of the vessel. For example, the enlarged portion canhave a non-cylindrical shape. As noted above, various embodiments of thescaffold including an enlarged portion can be used in the method.Additionally or alternatively, the method of treating a condition ofvessel includes: providing an intraluminal scaffold comprising agenerally tubular body with a lumen defined therethrough, the tubularbody having a compressed condition for delivery and an expandedcondition for implant within a vessel subject to a valve anomaly;deploying the scaffold within the vessel; and allowing the tubular bodyof the scaffold to conform to a wall of the vessel. For example, thestent can be formed from a degradable material (e.g., biodegradable,bioabsorbable, or resorbable material) or other polymeric material thatwill reduce in diameter following expansion for some period of time. Themethod is useful in situations in which a vein has developed adistension or bulge and there is a desire to allow the vein to return toits original shape or at least to a smaller diameter. In particular,this can be useful in the treatment of CCSVI by mitigating reflux causedby distensions or bulged sections within the internal jugular vein.

As mentioned above, a vein may be distended or enlarged in any number ofshapes that create a risk of blood accumulation and iron deposition;however, for purposes of illustration only the simple bulb shape shownin FIG. 6 will be discussed. In order to treat such a bulb 108, a stent100 having some amount of natural recoil can be delivered into andengage or conform to the bulb. This expansion can be produced using amedium to high pressure balloon 110 to force the entire vein segmenttoward a cylindrical configuration, or it can be deployed using anelastic balloon that would be more likely to conform to the shape of thebulb 108.

A certain degree of elastic deformation for the stent 100 during itsdeployment can be helpful. First, this would allow the stent 100 toconform optimally to the enlarged venous segment. Second, it wouldencourage the stent to recoil toward its initial shape followingdeployment into the vessel. A stent formed of a polymer may be suitablefor fabricating such a stent due to the ability to tailor the materialproperties until a desired effect is received. In addition, the stentcan be fabricated from a degradable material, which would allow thestent to resorb into the body tissue after the vein is recovered andrehabilitated toward its original condition. Thus, materials such aspoly(alpha-hydroxy esters), polylactic acids, polylactides,poly-L-lactide, poly-DL-lactide, poly-L-lactide-co-DL-lactide,polyglycolic acids, polyglycolide, polylactic-co-glycolic acids,polyglycolide-co-lactide, polyglycolide-co-DL-lactide,polyglycolide-co-L-lactide, polyanhydrides, polyanhydride-co-imides,polyesters, polyorthoesters, polycaprolactones, polyanydrides,polyphosphazenes, polyester amides, polyester urethanes, polycarbonates,polytrimethylene carbonates, polyglycolide-co-trimethylene carbonates,poly(PBA-carbonates), polyfumarates, polypropylene fumarate,poly(p-dioxanone), polyhydroxyalkanoates, polyamino acids,poly-L-tyrosines, poly(beta-hydroxybutyrate),polyhydroxybutyrate-hydroxyvaleric acids, combinations thereof,chitosan, PBT, 4-hydroxybutyrate, 3-hydroxybutyrate, or PEG can be used.

Alternatively, the stent 100 can be formed from a deformable or a shapememory material. Although both of these options will provide someremodeling benefit, given that they will both exhibit recoil, it iscontemplated that a shape memory material such as Nitinol can be moreuseful than a deformable material such as stainless steel because itwill exhibit greater recoil and thus more pronounced remodeling of thevein.

As shown in FIG. 7, after the stent 100 has been expanded within adistended vein 106, it can undergo some amount of recoil, therebyresizing the vein 106 toward a smaller size. In addition to theresilience of the stent material, the recoil can also result fromdegradation of the degradable material of the stent (if the stent or aportion of the stent is made of such material). The vein 106 will reducereduce in size as stent 100 undergoes recoil due to the development ofadhesion or ingrowth between the stent 100 and the vessel Alternatively,the recoil of the stent can be in response to a reduction in the vesseldiameter, e.g., the tubular body of the stent dynamically conforms tothe wall of the vessel during vessel relaxation due to adjustments influid flow. In either case, the tubular body of the intraluminalscaffold can recoil from its initial expanded condition over a period oftime, such as greater than one day.

The vein 106 shape may have any number of configurations. For example,it can be distended toward the shape shown in FIG. 8, which essentiallycreates a vein sac 114 between a proximal bulb segment 116 and distalbulb segment 118 of an internal jugular vein. Therefore, the bloodaccumulation in this section can contribute to CCSVI and potentially tounderlying diseases such as MS. Referring to FIG. 9, a stent 100 can bedeployed within the vein segment 114. The vein will adhere to the stentstruts and therefore be pulled inward by the stent struts as the entirestent structure undergoes gradual stent recoil. As a result, the vein106 can be remodeled toward its original shape, which will help mitigateor eliminate the blood accumulation or reflux that is present in thevein.

The degradable material for the stent above can be capable ofextravascular degradation. Thus, in the above method, the stent can beallowed to migrate through the vessel wall to be resorbed into thepatient anatomy. The remodeled vessel will then be free of foreignbodies and will be restored to its original function. The stent for thisembodiment can be formed from a material such as a PLLA, PLGA, and thelike. The stent can be positioned on a balloon catheter and deliveredinto the target vessel, such as the distended vein 142 shown in FIG. 18.When located at the treatment site, the stent can be expanded andbrought into contact with the vessel wall. As appreciated, the stent canhave an enlarged portion (e.g., which has a non-cynlindrical shape) whenexpanded as described in any of the various embodiments of the stents asdescribed above.

Referring to FIG. 19, the properties of the extravascularly degradablestent 140 are such that it will initially recoil toward a lower profile.When this recoil begins, the stent 140 will have already begun to adhereto, or resorb into, the vessel wall. Thus, a radial inward force will beexerted on the vessel wall and the vessel diameter will reduce alongwith the stent diameter. As the distended vessel reduces in diameter, itwill remodel and result in a smaller diameter vessel. This remodeledshape can help eliminate the reflux that exist in distended veins,thereby have improved function. As shown in FIG. 19, the degradablestent 140 can be delivered to the distended vein 142 using aconventional stent delivery catheter 144 which includes an expandablemember, such as an expandable balloon 146.

As shown in FIG. 20, as the stent 140 degrades over time and loses muchof its radial strength, it will tend to grow outward. This growth willenable the stent to migrate through the venous wall. The phenomenon ofstent migration through a venous wall has been confirmed withself-expandable stents. This migration is due to the outward load of thestent and the thin wall of a vein. Since the vein is unable tocounteract the outward motion of the stent, it tends to grow around thestent as the stent migrates outward.

Eventually, the stent 140 will migrate through the venous wall as shownin FIG. 21. Once the stent 140 has traveled into the extravascular spacesurrounding the vein, it will be able to resorb fully into the patientanatomy as illustrated in FIG. 22. It will be appreciated that in thiscase the internal surface of the remodeled vein will be completely freeof any foreign bodies caused by the stent procedure. Thus, the remodeledvein 142 will exhibit improved function and will be free of flowdisturbances or abrupt changes in stiffness that would otherwise be thecase in a stented vessel. Furthermore, because there is no stent in thevenous wall, there will be reduced risk of vessel injury if the patientis struck in the neck or otherwise physically traumatized in the neckregion.

In view of the above, a method is provided herein which includesselecting a patient demonstrating a symptom associated with a conditionselected from fatigue, chronic fatigue, venous insufficiency of the leg,chronic venous insufficiency, deep vein thrombosis, Alzheimers, adultonset dementia, Parkinsons, May-Thurner, Budd-Chiari, CCSVI, and MS, anddeploying an intraluminal scaffold in a vein having or subject to avalve anomaly believed to be associated with the symptom. For example,the scaffold can be deployed in a vein having one or more valves, suchas veins having valves which are atypical or irregular in function orotherwise insufficient. Such valves can be associated with a neck (e.g.,jugular), a leg, or a liver, among other things. As a particularexample, the vein can be an internal jugular vein.

In accordance with another aspect of the disclosed subject matter, amethod for fabricating a scaffold having a non-cylindrical section isprovided. The method includes providing a tubular body with a lumendefined therethrough, at least a length of the tubular body configuredto form an enlarged portion, and defining a plurality of cells in thetubular body to form an intraluminal scaffold capable of having acompressed condition for delivery and an expanded condition for implantwithin a vessel, the at least a length of the tubular body having theenlarged portion when in the expanded condition. For example, theenlarged portion can have a non-cylindrical shape.

Referring to FIG. 10, the tubular body, or stent tubing, of anon-cylindrical stent 122 can be used to fabricate the stent 120. Thestent tubing can be formed in various manners, such as blow molding,hydroforming, dip molding, and the like, as known in the art. Specificanatomies that may benefit from such a stent 120 include areas withbulges or distended portions, such as those that are common in thebulbous segments of the internal jugular vein. For purpose of examplesand not limitation, blow molding can be performed, in which asubstantially cylindrical tubing is inserted within a cavity having thedesired non-cylindrical form. The tubing is heated and pressurized untilthe material expands against the cavity walls. Subsequently, the tubingis cooled, allowing it to retain the shape of the cavity. In order toremove the non-cylindrical tubing from the cavity, a split mold designcan be used for the cavity. Split mold designs may include one or moreseams in the longitudinal or transverse direction. For example, ifformed in the longitudinal direction, there may be a split along thelength of the mold in two or more locations. Alternatively, if formed inthe transverse direction, a single split line can be produced.Alternatively, there may be multiple split lines, in the transversedirection for example, that allow the non-cylindrical form to becompartmentalized. That is, there may be a split line along twoshoulders on the tubing, which are spaced apart from each other in thelongitudinal direction.

It will be appreciated that the use of a blow molding process mayprovide structural advantages as well. For example, it is known that theblow molding may produce alignment and orientation of the polymer, whichresults in improved material strength. By varying the mold design andprocess, varied strength can be produced throughout the stent tubing.For example, separate portions of the tubing can be blow molded underseparate processes so that the amount of stretch, and thereforealignment and material strength can be thereby controlled. Note thatblow molding is not the only manner in which a non-cylindrical tubingcan be formed. Other processes, such as injection molding, dip molding,extrusion, casting, and any other well-known processes that can formnon-cylindrical tubing can also be used.

Referring to FIG. 11, after fabrication of the non-cylindrical tubing122 is complete, a stent structure can be formed from the tubing using acutting process. It is contemplated that laser cutting of the tubing ina manner traditionally used for stent cutting can be used. It will beunderstood that adjustments to the process may be made to accomplishthis process. For example, the laser head may need to move relative tothe tubing surface or other means of maintaining a cutting beam focus atthe stent tubing 122 surface will need to be devised to ensure that thestent 120 is properly formed from the tubing. Other methods of forming astent structure from a tube are known beside the use of laser cutting.For example, micro-machining is another suitable method.

Referring to FIG. 12, a non-cylindrical stent 120 is shown that has beenformed from a non-cylindrical tubing. The cell pattern on the stent canbe uniform or non-uniform across the stent, as desired. For example, ifthe stent includes both an enlarged portion and a cylindrical portion,the average cell size of the two portions can be different. Also, thecell pattern on the enlarged portion itself need not be uniform.

In addition to the use of polymeric materials in the formation of thisstent 120, such as the use of a degradable polymer stent materials, itis also possible to form a non-cylindrical stent/tubing from anon-polymeric material. For example, the stent tubing 122 can be formedfrom a deformable metal such as stainless steel or a shape memory metalsuch as Nitinol. In either case, a specialized process would be requiredto achieve the non-cylindrical form, which can be achievable through theuse of metal forming processes such as forging.

Alternatively, the tubular body can be obtained or prepared bydepositing tubular body material, e.g., a metal or metal alloy, on amandrel having a surface defining the enlarged portion. The depositioncan be by vapor deposition, electroplating or any other suitablemethods. The material can be deposited across the surface of the mandrelwith uniform or varied thickness and then cut as previously described toform the desired cell pattern. Alternatively, the deposition can also beaccomplished by depositing the tubular body material on select locationsof the surface of the mandrel such that the cell patterns of the stentare established during the deposition.

Referring to FIG. 13, a non-cylindrical stent 120 is anticipated to havemany useful benefits in the treatment of odd vascular anatomies and inthe treatment of veins in general. Hence, the stents disclosed hereincan be customized for the desired application. As shown in FIG. 14, afirst step in an exemplary process is to produce a cylindrical tube 126using the material from which a stent will be fabricated. This tubefabrication can be enabled through the use of an extrusion processutilizing exterior equipment 128 as shown, which has been developed andutilized for the creation of polymeric tubing. Alternatively, the tubing126 could be produced through other well known tubing manufacturingprocesses such as dip molding or gun-drilling.

In each case, the stent tubing 126 can be formed from a metal, but inthe case where degradation or resorption of the stent is desirable, itwill more likely be formed from a degradable polymer. Examples of suchmaterials include: poly(alpha-hydroxy esters), polylactic acids,polylactides, poly-L-lactide, poly-DL-lactide,poly-L-lactide-co-DL-lactide, polyglycolic acids, polyglycolide,polylactic-co-glycolic acids, polyglycolide-co-lactide,polyglycolide-co-DL-lactide, polyglycolide-co-L-lactide, polyanhydrides,polyanhydride-co-imides, polyesters, polyorthoesters, polycaprolactones,polyanydrides, polyphosphazenes, polyester amides, polyester urethanes,polycarbonates, polytrimethylene carbonates,polyglycolide-co-trimethylene carbonates, poly(PBA-carbonates),polyfumarates, polypropylene fumarate, poly(p-dioxanone),polyhydroxyalkanoates, polyamino acids, poly-L-tyrosines,poly(beta-hydroxybutyrate), polyhydroxybutyrate-hydroxyvaleric acids,combinations thereof, chitosan, PBT, 4-hydroxybutyrate,3-hydroxybutyrate, or PEG.

The tubular preform can be opened at one or both ends to permitpressurization of the tubing 126 during the next step of the process. Inthe case of having both ends open, a temporary seal or plug can beformed with one end 132 when the tubing 126 is pressurized.Alternatively, the tube 126 can be sealed and pressurized from bothends.

After forming the tube 122, it can be blow molded as shown in FIG. 15.The tube 122 can be inserted within a mold 130 having the form of thedesired final tubing shape. In this case, the mold 130 has a bulbousshape 132. The mold 130 can be cooled during the blow molding process.The cooling can be effected through the use of water channels (not shownin FIG. 15) that run through the form, by conductive cooling from asurrounding jacket, or by directing a fluid over the surface of themold, to name a few possibilities. This cooling is important because itwill help to cool the preform after it is formed against the moldsurface.

Formation of the tubing form is illustrated in FIG. 16. In oneembodiment, the process can be an extrusion blow molding process, suchthat the tube 122 is extruded concurrently with the blow molding, thusthe tube is 122 already heated to an appropriate temperature that willallow it to be deformed when pressurized. Alternatively, the preform canbe heated when it is placed within the mold. When the resin issufficiently heated, the preform is pressurized from at least one end tocause the entire preform to expand outward toward the surface of themold cavity 132. Once the preform contacts the mold cavity, it will becooled by the mold surface, and tubing will solidify in its final form.The part can then be ejected in its final form.

It will be appreciated that there are many different methods of blowmolding plastic components, and that the method of manufacturing stenttubing described herein is intended to encompass all of these. Forexample, in addition to extrusion blow molding, it is also possible touse injection blow molding and stretch blow molding. Furthermore,variations of these processes are possible, including continuousextrusion blow molding, intermittent blow molding, and many othervariations that one skilled in the art could employ to form anon-cylindrical tubing that is suitable for manufacturing a stentdevice.

After formation of the non-cylindrical stent tubing using the processdescribed above, the tubing 122 may then be used to form a stentstructure. As shown in FIG. 17, a laser can be directed toward thetubing surface to cut the desired pattern into the tubing structure 122.This step may require specialized laser technologies that will allow forcutting of a non-tubular surface. For example, either the position ofboth the laser source or the stent tubing can be maintained whileadjusting the focal point of the laser in the z-direction.Alternatively, one or both of the laser source or the stent tubing canbe adjusted along the z-direction in order to ensure that the focalpoint of the laser impinges on the tubing surface. Furthermore, theangle of either the laser source or the tubing axis can be changed inorder to ensure that the laser beam impinges basically perpendicular tothe tubing surface at all times.

After the stent structure 120 has been cut into the non-cylindricaltubular component, subsequent manufacturing processes can be performed.For example, there can be subsequent polishing steps to remove islandsor burrs from the stent struts. Additionally, there may be crimpingprocesses required to reduce the stent diameter in order to mate with adeployment balloon or a delivery sheath. These additional processes canbe developed as required or desired.

The stent can then be crimped and loaded over the balloon component of aballoon delivery system. Alternatively, the stent can be crimped andloaded into a delivery system sheath. The stent delivery system can thenbe advanced through the patient anatomy to deploy the stent at a targetpatient location. This deployment can be performed in a manner that iscommonly used for stent delivery systems, such as inflation of a ballooncomponent that expands the stent or retrieval of a sheath that allowsthe stent to self-expand to a final configuration.

In accordance with another aspect of the present application, a stent isprovided which includes a first annular element radially expandable withrespect to a longitudinal axis defined therethrough, a second annularelement radially expandable with respect to the longitudinal axis, andat least one axial strut connecting the first annular element and thesecond annular element, the at least one axial strut having sufficientflexibility to conform to a wall of a distended portion of a vessel.

Referring to FIG. 38, in an embodiment stent 260, a stent with a distalring 262 and a proximal ring 264 (flattened view) having a generallymeandering configuration as is well known in the stent art are connectedby one or more axial struts 266. These axial struts 266 have relativelylow radial strength and high flexibility in comparison to meanderingstruts. In a way, the axial struts act as end-supported beams with highspans. Thus, the axial struts can have sufficient flexibility to avoidforcing the venous wall outward excessively, and to conform to adistended portion, e.g., a non-cylindrical vessel wall.

As shown in FIG. 39, such a stent 260 can be used to treat the bulbousportion 268 of the internal jugular vein. The meandering stent rings canbe expanded to the diameter of the vein portions they were respectivelyimplanted, i.e. either within the proximal small diameter portion 270 orthe distal bulbous portion 268. The axial struts 266 spanning theserings 262 and 264 will conform to the tapered vessel wall.

It will be appreciated that although not shown, the vessel caneventually remodel to a smaller size that is more cylindrical. Forexample, in a case in which the stent is expanded across a bulge whereinthe axial struts support the bulge and the meandering stent rings areplaced on either side of the bulge, it is possible that the venous wallwould adhere to the axial struts. Thus, over time the axial struts canreduce in profile as they retract to their original shape, and thiswould cause the vein to remodel along with the struts.

As shown in FIG. 40, the flexibility and strength of the axial struts266 can be controlled by using additional radial connectors 272 featuresthat provide radial stability and control the unsupported span length ofthe axial struts. These radial connectors 272 will provide radialsupport as well. The location of the connectors 272 can be manipulatedto achieve the desirable flexibility or radial strength. In general, themore radial connectors 272 present, the stiffer the stent structure willbe.

In still another embodiment, as shown in FIG. 41, a stent 280 can beformed with axial struts 282 forming a bulbous portion 284. This can beaccomplished in one way by cutting the stent from a non-cylindricaltube. Alternatively, the bulbous shape of the struts can be achieved bydeploying the stent 280 with a bulbous balloon that forces the axialstruts outward into the arcuate configuration. One or more end rings 286and 288 can be attached to the axial struts 282. This can beaccomplished, for example, with a secondary balloon that is deployedinto the stent after the initial stent expansion.

This stent can be formed from multiple material types, including metalsand polymers of all types. Further, different portion of the stent canbe formed of different materials. For example, the stent can includes ahybrid structure in which one or more end rings (266 and 288) are formedfrom a balloon expandable stent structure. These balloon expandablestructures are preferably fabricated from materials such as stainlesssteel or cobalt chromium, which arc able to plastically strain in orderto reset the stent structure to a larger diameter. The structure itselfcan be designed to accommodate a large range of diameters. For example,it can be expanded to a range of between about 5 mm and 20 mm withsufficient radial strength to ensure that the stent can prop open avenous structure. In comparison, the scaffold struts 282 can be formedfrom a self-expandable material. For example, the struts can be formedfrom a nickel-titanium alloy such as nitinol. In this way, the strutscan be formed in an arcuate shape. In the case of a bulging vessel, thiswill result in a stent that closely conforms to the bulge. In the caseof a non-bulging vessel or one in which the struts are placed across thestenosed venous valves, the arcuate struts will provide higher radialstrength and ensure that the valves remain open.

Various bonding processes can be used to associate the end rings andarcuate strut segments. For example, thermal welding can be used to bondthe components. Alternatively, the components can be bonded withadhesive. Also, the components can be associated through mechanicalmeans such as by tying them together with a third component, e.g.suture.

Alternatively, both the end rings and the axial struts can be formed aself-expandable material, such as nitinol stent. Nitinol can be formedin either an austenitic or martensitic phase. In the austenitic phase,the nitinol exhibits the shape-memory characteristics mentioned above.However, when the nitinol is in the martensitic phase, it behaves in aplastically deformable manner, and thus can be used to form a stent ringthat is balloon expandable. Therefore, the end rings can be formed fromnitinol in its martensitic state and the arcuate strut segments can beformed from nitinol in its austenitic state.

An all-nitinol stent structure is advantageous in at least two ways.First, the thermal welding of nitinol to nitinol can be performed moreeasily than the process of bonding nitinol to a dissimilar material. Inaddition, a stent formed from a single material is less likely toencounter galvanic effects that occur between dissimilar materials, andthis will make the stent less susceptible to in-vivo corrosion.

Deployment of a hybrid stent as above can be performed using a balloonand/or a balloon-sheath combination. In the case of a balloon catheter,the stent can be crimped on the balloon element in a manner typical ofballoon expandable stents. During the crimping process, the stent can bestretched such that the arcuate segments straighten and conform to theballoon profile. The struts will remain straightened due to thefrictional securement between the end rings and the balloon element.Alternatively, a sheath can be used in combination with the balloonelement to ensure that the struts remain in a low profile. In this case,the sheath is placed over the crimped stent to resist any tendency ofthe struts to bow outward during device delivery.

A stent of this type can be deployed in a manner that promotesconformance to the vessel wall. For example, the proximal and/or distalend of the stent can be deployed prior to the opposing end of the stent.Thus, a single ring can be deployed at a time. By doing this, when onering is deployed it will allow the arcuate struts to expand wholly orpartially. Therefore, the arcuate struts will conform closely to thevessel near the deployed end ring. When the second end ring is deployed,the struts will be able to gradually deploy into the vesselsimultaneously. This reduces the risk that the struts can be stretchedor bunched during simultaneous expansion of the end rings. Therefore,overall conformance to the vessel can be improved. In order tofacilitate this type of expansion, there may be a benefit in using amulti-balloon system. Therefore, one balloon will engage each endseparately, allowing the ends to be deployed separately. Alternatively,a single balloon can be used, however a sheath can be placed over thestent and retracted as desired to allow one ring to be exposed to thevessel while the other ring is covered. The exposed ring can thereforebe expanded by inflating the single balloon. After expanding one ring,the sheath can be retracted further to expose the second ring and thatring can be deployed by additional balloon inflation.

Further still, it is contemplated as disclosed herein that the stent canbe formed of multiple independent ring sections of varying sizes. Theindependent rings can be that are separately deployed in the vessel,whereby certain locations along the vein receive a ring section with afirst radial diameter and the other locations along the vein receive aring section of a second radial diameter greater than that of the othersections.

In accordance with another aspect of the disclosed subject matter, thestents or scaffolds as described herein further include a drug ortherapeutic substance selected from those described below for treating,ameliorating, or inhibiting a condition of concern of a patient. Thetherapeutic substance can be coated on the scaffold or otherwiseincorporated. For example, the therapeutic substance can be included inreservoirs formed on the surface of the scaffold, or impregnated in acoating of a polymer layer coated on the scaffold.

Therapeutic substances as used herein include biologically active agentsand can be, for example, therapeutic, prophylactic, or diagnosticagents. As used in this document, the therapeutic substance includes abioactive moiety, derivative, or metabolite of the therapeuticsubstance.

Examples of suitable therapeutic and prophylactic agents includesynthetic inorganic and organic compounds, proteins and peptides,polysaccharides and other sugars, lipids, and DNA and RNA nucleic acidsequences having therapeutic, prophylactic, or diagnostic activities.Nucleic acid sequences include genes, antisense molecules, which bind tocomplementary DNA to inhibit transcription, and ribozymes. Otherexamples of therapeutic substances include antibodies, receptor ligands,and enzymes, adhesion peptides, oligosaccharides, blood clottingfactors, inhibitors or clot dissolving agents, such as streptokinase andtissue plasminogen activator, antigens for immunization, hormones andgrowth factors, oligonucleotides such as antisense oligonucleotides andribozymes and retroviral vectors for use in gene therapy.

In other examples, the drugs or therapeutic substances inhibitvascular-smooth-muscle-cell activity. More specifically, the therapeuticsubstance may inhibit abnormal or inappropriate migration orproliferation of smooth muscle cells leading to restenosis inhibition.Therapeutic substances can also include any substance capable ofexerting a therapeutic or prophylactic effect. For example, thetherapeutic substance could be a prohealing drug that imparts a benignneointimal response characterized by controlled proliferation of smoothmuscle cells and controlled deposition of extracellular matrix withcomplete luminal coverage by phenotypically functional (similar touninjured, healthy intima) and morphologically normal (similar touninjured, healthy intima) endothelial cells.

The therapeutic substance can also fall under the genus ofantineoplastic, cytostatic or anti-proliferative, anti-inflammatory,antiplatelet, anticoagulant, antifibrin, antithrombin, antimitotic,antibiotic, antiallergic and antioxidant substances.

Antineoplastic or antimitotic examples:

-   paclitaxel-   docetaxel-   methotrexate-   Azathioprine-   Vincristine-   Vinblastine-   Fluorouracil-   doxorubicin hydrochloride-   mitomycin

Antiplatelet, anticoagulant, antifibrin, and antithrombin examples:

-   Heparinoids-   Hirudin-   Argatroban-   Forskolin-   Vapiprost-   Prostacyclin-   prostacyclin analogues-   Dextran-   D-phe-pro-arg-chloromethylketone (synthetic antithrombin)

Dipyridamole g

-   lycoprotein IIb/IIIa platelet membrane receptor antagonist antibody    recombinant hirudin and thrombin inhibitors

Cytostatic or Antiproliferative Agent Examples

-   Angiopeptin-   angiotensin converting enzyme inhibitors-   cilazapril-   lisinopril-   actinomycin D-   dactinomycin-   actinomycin IV-   actinomycin I₁-   actinomycin X₁-   actinomycin C₁-   actinomycin D derivatives or analogs

Other therapeutic substances include

-   calcium channel blockers-   nifedipine-   Colchicines-   fibroblast growth factor (FGF) antagonists-   omega 3-fatty acid-   Fish oil-   Flax seed oil-   histamine antagonists-   lovastatin-   monoclonal antibodies (such as those specific for Platelet-Derived    Growth Factor (PDGF) receptors)-   Nitroprusside-   phosphodiesterase inhibitors-   prostaglandin inhibitors-   Suramin-   serotonin blockers-   Steroids-   thioprotease inhibitors-   triazolopyrimidine (a PDGF antagonist)-   nitric oxide-   alpha-interferon-   genetically engineered epithelial cells-   antibodies such as CD-34 antibody-   abciximab (REOPRO)-   progenitor cell capturing antibody-   pro-healing therapeutic substances (that promotes controlled    proliferation of muscle cells with a normal and physiologically    benign composition and synthesis product)-   Enzymes-   anti-inflammatory agents-   Antivirals-   anticancer drugs-   anticoagulant agents-   free radical scavengers-   Estradiol-   steroidal anti-inflammatory agents-   non-steroidal anti-inflammatory-   dexamethasone-   clobetasol-   aspirin-   Antibiotics-   nitric oxide donors-   super oxide dismutases-   super oxide dismutase mimics-   4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (4amino-TEMPO)-   Tacrolimus-   Rapamycin-   rapamycin derivatives 40-O-(2-hydroxy)ethylrapamycin (everolimus)-   40-O-(3 -hydroxy)propyl-rapamycin-   40-O-[2-(2-hydroxy)ethoxy]ethyl-rapamycin-   40-O-tetrazole-rapamycin-   Zotarolimus (TM)-   cytostatic agents-   Antiallergic agent such as permirolast potassium.

In particular embodiments, the therapeutic substance can include one ormore of fondaparinux (Arixtra®), Enoxaparin, Bivaliruden, a factor Xainhibitor, a collagenase (e.g., Xiaflex®), and endopeptidase.

In a further aspect, the disclosed subject matter also provides methodsand devices for deploying a medical device. The method includesestablishing an open condition of a valve in a vessel of a patient,moving a medical device through the opened valve; and deploying themedical device at a target site. Each of the operations above iscompleted without negatively impacting the function of the valve. Themethods herein can be used in any vessel having one or more valves. Forpurpose of illustration, reference will be made to a venous systembelow.

The medical device to be deployed can be any of the scaffolds asdescribed above, as well as other treatment devices such as surgicaldevices, balloons, implants, grafts, or the like. The method allows forminimization of trauma to the venous valves. By reducing trauma to thevalves, a stent, balloon, or other medical device can be used to treat avenous condition, e.g., venous insufficiency, while minimizing damagethat could be counterproductive to the goals of the vein treatment.

One exemplary target site is an internal jugular vein as discussedabove, the distension of which is associated with the conditions ofCCSVI and can be treated by employing the various embodiments of stentsas described above. To access a target site in an internal jugular, avascular access device such as an introducer sheath can be introducedvia the external jugular, e.g., via an access path (depicted by thebroken line 350 in FIG. 50) as shown in FIG. 50. Thus, the access devicecan be tracked through collateral veins stemming from the externaljugular vein into the descending internal jugular vein. As these deviceswill be traveling in the antegrade direction, there will be minimal riskof valve damage during their delivery. FIG. 51 illustrates how thisaccess can be made in a patient's neck. The introducer sheath 352 can beinserted using well known techniques similar to those used to gainaccess to a patient's femoral or radial arteries. This can beaccomplished through the initial introduction of an introducer needleand a guidewire, and the subsequent exchange of an introducer sheath forthe introducer needle. Thus, a route of access is gained within thevenous anatomy and guidewires or devices can be delivered into the veinsas needed.

Referring back to FIG. 50, it will be appreciated that the pathwaythrough the network of veins and arriving at the target location mayvary depending on the circumstances of individual cases. A variety ofindependent collateral veins exist that interconnect the jugular veinsin the venous network, and therefore a medical device can be insertedand tracked through any of these veins to reach the desired destination.However, it will be appreciated that under all circumstances, thismethod prefers that the device will be tracked through each of theseveins in an antegrade direction whenever possible. The external jugularvein is anticipated to be a useful site of introduction because it iscovered by comparatively less tissue relative to the internal jugularvein and perhaps as compared to other collaterals as well. Therefore,introduction into the external jugular vein should be easier tovisualize, easier to achieve, and should also cause less tissue traumaas compared to other access points. Nonetheless, although the externaljugular vein is a preferred access site given its relative size andlocation, other veins can be used for access to the internal jugularvein as well. In an alternative embodiment, access to the internaljugular vein can be made directly, or access can be made into one of thecollateral veins other than the external jugular vein.

Establishing an open configuration of the valve can, for example,includes altering fluid flow in the vicinity of the valve, as well asother approaches as further explained below. In one embodiment, themethod includes drawing blood flow in an antegrade direction, e.g., byusing suction, thereby opening the venous valves. While the venous valveis opened, a guidewire or other treatment device can be advanced throughthe valve in a retrograde direction using a delivery device. Thetreatment device thus can be delivered without damaging (e.g., tearingor snagging) the leaflets. After deploying the medical device, thedelivery device, such as a catheter, can be retrieved or removed.Alternatively or additionally, the medical device can also be retrievedor removed while the valve is in an open position, or the medical devicecan be implanted and remain

Referring to FIG. 42, an exemplary embodiment of a device is shown. Thedevice 300 comprises an elongated catheter body 302 having a distalportion 304 and a proximal portion 306. The proximal portion 306 caninclude one or more ports 308 for communicating with the distal catheterend 304. For example, one port can be a device port 308 a, which allowsa medical device such as a guidewire (see FIG. 44) to be advancedthrough the port into a lumen that runs the length of the catheter body302. The medical device can be advanced through the device port 308 aand catheter lumen to exit the distal end 310 of the catheter device. Inaddition, there may be an inflation port 308 h near the proximal endthat allows for an inflation fluid to communicate with the distalcatheter portion 304 through an inflation lumen disposed within thecatheter body.

The distal portion 304 of the catheter can include an occlusion balloon312. This balloon 312 is can be formed from a compliant material, suchas an elastomeric material. The balloon 312 is placed in communicationwith the inflation lumen of the catheter body, such that introduction ofan inflation fluid through the inflation port 308 b will cause theballoon 312 to expand. When positioned within a body vessel, expansionof the balloon 312 can cause the vessel to be occluded.

In addition, a suction port 308 c can be positioned near the proximalportion 306. This suction port 308 c can communicate with a suctionlumen disposed within the catheter body. The suction port 308 c can havea vacuum applied to it by attached a syringe (not shown) to the portconnector 308 c and drawing a vacuum within the syringe. It will beappreciated that doing so while the catheter is located within a veinwill cause blood to be drawn through the suction lumen into the syringe.

A method of using the device to draw a suction within a patient anatomyis shown in FIG. 43. The device can be advanced through the patientanatomy until the distal end is located near and downstream of a venousvalve. The occlusion balloon that is disposed near the distal end of thedevice can be expanded by introducing an inflation fluid through theinflation port. As the balloon expands, it will contact the vessel walland form a seal in the vessel, which prevents the antegrade flow ofblood.

As shown in FIG. 44, when the vessel is occluded, a suction can be drawnthrough the suction port using a syringe or another apparatus that canproduce a vacuum. The suction will result in the increased flow of bloodin the antegrade direction as the blood enters the suction lumen of thecatheter and is drawn into the syringe near the proximal end of thedevice. While this suction is produced, the valves of the vein will tendto open due to the continuous antegrade blood flow depicted by arrows314 or FIG. 44. During this time when the valves are opened, a guidewire316 or another device can be advanced through the device lumen into thevein in a retrograde direction. The device 316 can advance freelythrough the valves because they will be dilated such that the passage ofthe device 316 is less likely to snag on the valve, or if it does, ismore likely to deflect away and move through the vessel.

The method of drawing suction and advancing a device to cross through avalve without damaging it can be performed repeatedly in an intermittentfashion. For example, suction can be drawn at each point when the deviceis adjacent to, and ready to cross through, a valve. Alternatively,suction can be drawn continuously the entire time that the device isbeing advanced through the vessel.

After a guidewire 316 is placed through the length of vessel that isintended to be treated, a medical device such as a stent or ballooncatheter can be advanced over the guidewire and through the vessellength including the venous valves to the treatment site. This deliverycan be aided through the use of suction as described above, as well. Inthis case, depending on the size of the medical device, a suctioncatheter of appropriate size and configuration can be used toaccommodate the size and configuration of the medical device.

In an alternative embodiment, establishing the open configuration of thevalves can be via the creation of a positive pressure within a vessel,e.g., introducing a fluid in an antegrade direction from a locationupstream of the valve. Referring to FIG. 45, an exemplary embodiment ofa device for creating a positive pressure is shown. The device 320comprises an elongated catheter body 322 having a distal portion 324 anda proximal portion 326. The proximal portion 326 may include one or moreports 328 that are useful for communicating with the distal catheter end330. For example, one port 328 a can be a device port, which allows adevice such as a guidewire to be advanced through the port into a lumenthat runs the length of the catheter body. The device can be advancedthrough the device port 328 a and catheter lumen to exit the distal end330 of the catheter device. In addition, there can be an inflation port328 b near the proximal portion 326 that allows for an inflation fluidto communicate with the distal catheter portion 324 through an inflationlumen disposed within the catheter body.

The distal portion 324 of the catheter can include an occlusion balloon332. This balloon 332 is can be formed from a compliant material, suchas an elastomeric material. The balloon 332 is placed in communicationwith the inflation lumen of the catheter body, such that introduction ofan inflation fluid through the inflation port 328 b can cause theballoon to expand. When positioned within a body vessel, expansion ofthe balloon 332 can cause the vessel to be occluded.

Alternatively, the occlusion balloon need not be used, and instead theinflation port 328 b can be used to communicate a fluid into the vesselthat pressurizes it in order to open the venous valves. In this case,the “inflation port” can also be referred to as a “pressurization port.”However, in the case where the catheter 320 does include an occlusionballoon 332, the catheter may further comprise a pressurization port 328c positioned near the proximal end of the catheter. This pressurizationport 328 c can communicate with a pressurization lumen disposed withinthe catheter body 322. The pressurization port 328 c can attach to asyringe or another fluid source (not shown) in order to introduce afluid or a gas into the patient anatomy through the distal end of thepressurization lumen. It will be appreciated that doing so while thecatheter is located within a vein will cause blood to flow in thedirection of decreasing venous pressure, i.e. when the distal end isplaced above the jugular valves it will force blood in the antegradedirection. Arrow 334 shows the direction of fluid flow introduced by thecatheter device.

A method of using the device to introducing a fluid in an antegradedirection is illustrated in FIG. 46. The device such is a guidewire 336,can be advanced through the patient anatomy in an antegrade directionuntil the distal end is located near a venous valve. Access in anantegrade direction can be achieved in multiple ways. For example, thecatheter can be introduced into the superior portion of the jugular veinusing an introducer sheath placed in the neck of the patient.Alternatively, access can be achieved by first delivering the catheterthrough the external jugular vein or other collateral veins in order tointroduce it in an antegrade direction in the internal jugular veinwhere those vessels meet. This approach can be used to access otherveins in the antegrade direction as well.

After delivering the catheter in the antegrade direction within thetarget vessel, the occlusion balloon 322 disposed near the distal end ofthe device can be expanded by introducing an inflation fluid through theinflation port 328 b. As the balloon 332 expands, it will contact thevessel wall and form a seal in the vessel, which prevents the antegradeflow of blood. It will be appreciated that this step can be omitted inthe case of a device lacking an occlusion balloon, or in cases where thephysician does not find it necessary to occlude the vessel, but wouldprefer to simply pressurize the vessel without the aid of occlusion.

As shown in FIG. 47, when the vessel is occluded, positive pressure canbe generated in the target vessel by introducing a fluid at a locationproximate and upstream of the valve by a syringe or another fluidsource. The pressure will result in the increased flow of blood in theantegrade direction as the injected fluid increases the volume of fluidand flow within the target vessel. While this flow is produced, thevalves of the vein will tend to open due to the continuous antegradeblood flow. During this time when the valves are opened, the guidewireor another device 336 can be advanced through the device lumen into thevein in a retrograde direction. The device can advance freely throughthe valve without causing permanent damage to the valve because thevalve will be dilated such that the passage of the device would not snagon the valve, or if it does, is more likely to deflect away and movethrough the vessel.

The method of producing increased antegrade flow and advancing a deviceto cross through a valve without damaging it can be performed repeatedin an intermittent fashion. Fluid injection can be made at each pointwhen the device is adjacent to, and ready to cross through, a valve.

Alternatively, fluid injection can be made continuously the entire timethat the device is being advanced through the vessel.

After a guidewire 336 is placed through the length of vessel that isintended to be treated, a medical device such as a stent or ballooncatheter can be advanced over the guidewire and through the vessellength including the venous valves to the treatment site. This deliverycan be aided through the use of positive flow as described above, aswell.

In an alternative embodiment, establishing an open configuration ofvalves can be achieved by occluding a body lumen (e.g., a non-targetvessel) proximal to and fluidly coupled with the target vessel in orderto increase flow of blood through the target vessel. This increasedblood flow or pressure will dilate the target vessel, which will be moreconducive to passage of the guidewire in a retrograde direction withoutdamaging the valve leaflets.

FIG. 48 illustrates an example of the venous system in the neck regionin which the jugular veins empty into the brachiocephalic vein. Duringthe normal function of these veins, blood flow is in an antegradedirection as blood is pulsed through the body. During this time, thevenous valves will open to permit the forward motion of blood.Retrograde flow of blood through the venous valves is prevented by thevalve leaflets. These leaflets are capable of withstanding some backpressure, in order to ensure that blood is moved forward rather thansimply pulsed back and forth. Therefore, the venous valves do not remainopen at all times, but instead will open and close in synchronizationwith the flow of blood.

In order to prevent damage to the venous valves during retrogradedelivery of a medical device, it is desirable for the valves to beopened. As illustrated in FIG. 49, one or more non-target vessels can beoccluded, preferably in the region where the blood empties into thebrachiocephalic vein on its way to the heart. The occlusion willredirect the flow of blood into other veins in order to ensure that thecirculatory capacity of the vascular system remains constant. Byredirecting this blood, at least some portion of the redirected bloodwill enter the target vessel. Thus, the flow through the target vesselwill increase as a result of the reduction in flow through thenon-target occluded vessel. As the venous valves are dilated afterocclusion of a non-target vessel, a medical device can be delivered in aretrograde direction through the valves with less risk of damage to thevalves. This is due to increased cross-sectional area of the vessel,which allows the crossing of a device. Therefore, the treatment regionof the target vessel can be reached with greater ease and with less riskof residual vessel damage.

It is appreciated that more than one non-target vessel can be occludedin order to urge the dilation of the target vessel. The more blood isredirected toward the target vessel, the greater the chance that thevenous valves will open entirely and permit passage of a medical devicein the retrograde direction without damage. It will also be appreciatedthat although it is preferable that the venous valves will open entirelyin the target vessel, partial dilation of the vein is also anticipatedto ease device passage by reducing the likelihood that the device willsnag and tear a venous valve.

Various techniques of occluding the non-target vessels can be used. Forexample, a balloon catheter can be used to achieve occlusion. A varietyof balloon catheters exist which have compliant, non-compliant, orsemi-compliant balloons. All of these varieties can be suitable forachieving occlusion. Furthermore, filter devices or expanding frameswith occlusive sheaths can be used as well. When these frames areexpanded within the patient anatomy, they will occlude their respectivevessels and redirect blood flow. The redirected blood flow will causethe valves in connected vein to open, allowing a medical device such asa guidewire 342 and catheter (not shown) to be placed in the connectedvein to allow a vascular procedure to be performed therein. Still otherocclusive devices exist or can be developed by one skilled in the art inorder to perform the occlusion.

In an alternative embodiment, establishing the open configuration of avalve includes temporarily expanding an expandable cuff within the valvewithout permanently impacting the function of the valve. For example, adevice can be provided with an expandable distal member having an outersurface and a central opening. The distal member can be used to expand avenous valve to allow a treatment device to be passed through the valvewithout causing damage to it. The valve can be expanded by the distalmember when it is deployed within the valve, thereby causing the outersurface of the distal member to press upon the valve leaflets. While thedistal member is expanded against the leaflets, the treatment device canbe passed through the central opening of the distal member in order toaccess anatomies beyond the valve without damaging the valve during itstravel. Such an embodiment is illustrated in FIG. 57. The device 450includes an elongated catheter shaft 452 having a proximal end 454 anddistal end 456. The catheter shaft 456 may further include one or morelumens capable of communicating fluids or bodies between the proximaland distal ends of the shaft.

An expandable distal member 458 can be positioned near the distal end ofthe catheter shaft. The distal member 458 can be a cuff, for example,that can be expanded or contracted between a delivery and deploymentstate. Expansion of the cuff 458 can occur, for example, through theintroduction of a fluid into the cuff body, which produces inflation ofthe cuff 458 and expands it into the deployment state. Introduction ofthe fluid that enables this expansion may be affected by the delivery ofan inflation fluid such as contrast media or saline into the cuffthrough an inflation lumen disposed within the catheter shaft. Theinflation lumen can accordingly be connected to an inflation port 460disposed near the proximal end of the catheter shaft. It is contemplatedthat this inflation port 460 may have a connection or fitting, such as aluer fitting by example which permits it to be removably coupled to afluid source such as a syringe device.

Referring to FIG. 58, a perspective view of an embodiment of a cuffmember 458 is shown. The cuff member 458 can be generally tubular inshape when it is expanded into the deployed configuration. The tubularshape thus includes an outer surface that can be deployed against thevalve leaflets and surround venous wall, and an internal cylindricalopening that allows a device to be passed through the cuff while it isexpanded.

Various materials can be used to create the cuff member. For example, itis contemplated that typical balloon materials used in the manufactureof medical devices are particularly well suited to this application.This includes balloon materials of the compliant, semi-compliant, andeven the compliant variety, which are well known in the art.

A method of delivering and deploying the device 450 within a patientanatomy is shown in FIG. 59. Here, the device 450 is first delivered ina retrograde fashion through the external jugular vein and othercollateral veins until it reaches the internal jugular vein. It will beappreciated that alternative routes can be used to allow the device toenter the target vessel in a retrograde direction. For example, thedevice 450 can be introduced directly into the target vessel, or it canbe introduced in an antegrade direction into a collateral vessel,through a venous puncture and access sheath positioned in the neck ofthe patient.

Once the device is positioned within the target vessel and the cuffmember 498 is advanced into the valve or valves that must be crossed,the cuff member can be deployed. Again, this can be effected through theintroduction of an inflation fluid in one embodiment. In an alternativeembodiment, the cuff 458 can include an expandable framework, forexample a frame comprised of a nitinol mesh, which could be expanded ina manner similar to that used for filter medical devices orself-expandable stent devices. In any case, once the cuff is expanded,it will press upon the valve leaflets and cause them to open toward thevein wall.

After the vein leaflets are opened, a treatment guidewire 462 and device464 can be delivered in a retrograde direction through the cuff openinginto the target anatomy. Alternatively, the treatment guidewire 462 anddevice 462 can be positioned adjacent to the inflated cuff member 458.After performing the desired procedure, which may for example by anangioplasty or stenting procedure of the target anatomy, the treatmentdevices 462 and 464 can be removed through the cuff and from the patientanatomy. It may also be possible to retrieve the cuff 458 from thepatient anatomy while the treatment devices are still in place, sincetheir retrieval will require that they be moved in the antegradedirection and is much less traumatic to the venous valves. Followingretrieval of the treatment devices, the cuff member 458 can becontracted into a low profile configuration and it can be retrieved fromthe patient anatomy through its access route.

In accordance with another aspect of the subject matter, a method ofdeploying a medical device across a plurality of valves while minimizingtrauma to these valves is provided. The method of deploying a medicaldevice across a plurality of valves of a vessel of a patient,comprising: providing a catheter having an inner shaft member and anouter shaft member co-axially disposed and axially moveable relative toeach other; positioning the catheter in a vessel having a plurality ofvalves including a first valve and a second valve; advancing a distalend of the outer shaft member across the first valve without permanentlyimpacting the function of the first valve; moving the inner shaft memberaxially relative to the outer shaft member; and advancing a distal endof the inner shaft member across the second valve without permanentlyimpacting the function of the second valve.

Referring to FIG. 52, a plan view of an exemplary telescoping catheter400 is shown. The catheter has at least two catheter shafts placedconcentrically relative to one another. The number of individualcatheter shafts can be varied depending on the length of vessel that onewould like to access. For example, if the operator intends to access atarget site that requires passage through four venous valves, it may bebeneficial to have a catheter with at least four independent cathetershafts. In the embodiment of FIG. 52, three catheter shafts 402, 404 and406 are shown. The figure does not illustrate the proximal connectionsthat the catheter can be fitted with to improve ease of use andfunction, but it will be appreciated by one skilled in the art thatvarious connectors can be used.

A telescoping catheter 400 such as the one shown in FIG. 52 may includea proximal connection (not shown) that allows the catheter to beconnected to a fluid source, such as a syringe. In this case, theconnection may include a luer fitting (not shown) that can be coupledwith a syringe so that fluid can be dispensed through the catheter.

A cross-sectional view taken about line A-A of FIG. 52 is shown in FIG.53. This illustrates the nested configuration of the telescopingcatheter shafts 402, 404 and 406. As shown, there are at least threeshaft members that are positioned concentrically. These shaft memberscan be advanced and retracted relative to one another by manuallyadvancing or retracting the catheter shafts near their proximal ends. Bydoing so, the overall catheter length can be adjusted.

Referring to FIG. 54. the catheter can first be advanced through thepatient anatomy until its distal end 408 is positioned near a valveleaflet. This can be done over a guidewire 410 that is placed in theanatomy first. The guidewire may thus be inserted through the entiretarget vessel length, or it may first be advanced only to the firstvalve to be advanced through in the manner described below.

Once the distal end 408 is positioned near the valve leaflet, the outershaft member 402 can be slowly advanced through the valve leaflet. Thedistal end of the catheter (e.g., the distal end of each of the shaftmembers 402, 404, and 406) can be formed with an atraumaticconfiguration (not shown) that allows it to be advanced through theleaflet without caused leaflet damage. This atraumatic configuration canbe formed through the use of a taper or a radius to allow them to beplaced through the valve leaflets without puncturing or tearing them.Once the distal end of an outer shaft member is advanced through a valveleaflet, it is preferable that it not be advanced further, since thefriction between the leaflet and the catheter outer surface could causethe leaflet to drag (e.g., in a retrograde direction), invert, tear, orotherwise be damaged.

When the first valve is successfully crossed, the internal nested shaftmembers can be advanced. The motion of these internal catheters will notresult in valve tearing because they are separated from the valves bythe outer catheter. Therefore, they can be advanced up to the next valvethat must be crossed, as shown in FIG. 55. Again, this advancement canbe achieved with or without the use of an internal guidewire 410. Whenthe next valve is reached, the distal end of an inner shaft member 404can be advanced through the valve slowly to avoid damaging the valve.Again, once the valve is crossed, the shaft members that are internal tothe previously advancing shaft can then be moved forward to repeat thecrossing procedure at the next valve. This method of advancing throughthe valves can be continued until the target vessel region is reached.

As shown in FIG. 56, after the target site is reached through the venousvalves, a treatment device such as a balloon catheter or stent deliverysystem 412 can be inserted through the telescoping catheter to bepositioned at the target site. The treatment device can then be deployedto treat the patient in the target area.

Recovery of the telescoping catheters can be made by retracting each ofthe catheter shaft members, e.g., in the reverse order as describedabove, until the entire telescoping catheter is removed from the patientanatomy.

Further to the various devices and methods of the disclosed subjectmatter as set forth above, a number of alternative methods of treatment,as described below, can be used as therapies for CCSVI for removing ordisplacing the obstructions within the venous system that cause bloodreflux:

Thrombus Disintegration: This device category is generally directed atthe use of thombolysis in order to restore normal blood flow in avessel. For example, a catheter may be positioned near the site ofocclusion in an internal jugular vein or another venous location that isresponsible for producing blood reflow and CCSVI. The catheter candispense medicaments to the venous location in order to dissolve bloodclots or thrombus in those locations in order to restore blood flow.Numerous device embodiments can be used for this treatment. As anexample, a double balloon occlusion catheter can be used in order toisolate the obstructed area for delivery of a lytic agent. Followingdelivery of the agent and the subsequent thrombus dissolution, thedissolved material may then either be allowed to pass into the distalvasculature by deflating the occlusion balloons or it may be removedthrough suction. It will be appreciated that thrombus disintegration canalso be caused mechanically. For example, a device having a rotatingwire may be used to act as a whisk within the vessel in order todisintegrate thrombus that is formed along the venous wall or disposedwithin the vein. Similar devices are used in the treatment of deep veinthrombosis. It may be beneficial to use a wire fabricated from aflexible material, such as nitinol. Furthermore, the device may easilyuse multiple wires to accomplish the desired task.

Thrombus Suction: Thrombus suction can be performed either before orafter the occluded venous segment is treated with a lytic agent todissolve the resident thrombus. In one example, a thrombolysis cathetermay include an additional lumen with a port positioned near the area inwhich lytics are dispensed. By drawing a vacuum through that lumen, anydissolved thrombus can be removed from the vasculature. Alternatively, asuction catheter may be deployed prior to dissolution of any thrombus.By positioning the distal end of the catheter near the occluded vesselportion and drawing a vacuum, the clots or thrombus can be suctionedinto the catheter and removed from the anatomy.

Covered Stent or Stent Graft: Another category of devices that would behelpful for treating the anatomies that are prevalent in CCSVI patientsare covered stents or stent grafts. These devices are stent structureswith a covering that is either a biological or synthetic substance. Thecovering is generally a thin film that can be adhered or otherwiseconnected to at least one location on the stent structure. Furthermore,the covering may be porous or non-porous and it may be loaded with apro-healing or therapeutic agent, or not. By deploying a device of thistype within an obstructed vein of a CCSVI patient, the obstruction canbe opened to prevent blood reflow. This type of device can beparticularly useful in the case of venous treatment because it willensure that a vein valve will be opened up sufficiently in the casewhere the device is deployed across a valve. Therefore, the valve willnot be allowed to recoil back into the vessel in order to obstruct bloodflow and create reflux.

Atherectomy: Atherectomy can be a useful treatment for CCSVI because itallows obstructive tissue to be cut and removed from the patient,thereby creating a fully opened vessel and mitigating any risk of bloodreflux. Numerous device types exist to allow this treatment, for examplea directional-type atherectomy catheter can be used or a rotoblator-typedevice may be used, as well. In either case, the purpose of theatherectomy device is to resect the obstructive tissue that is causingvenous obstruction. This tissue may be, for example, a lesion or a valveleaflet. In any case, after the tissue is resected it can either beremoved from the patient or allowed to simply pass downstream in theblood flow. After removal of the tissue, the vein is anticipated to nolonger have reflux caused by the removed tissue. Therefore, this mayproduce a beneficial impact on blood reflux and consequently multiplesclerosis.

Filter Device: It is contemplated that a filter device may be used inconjunction with one or more of the devices to ensure that the removedobstructive tissue is retrieved and removed from the patient. Forexample, a filter device can be used to capture tissue that has beenablated by a rotational-type atherectomy device, in order to ensure thatthe tissue is removed from the patient, as opposed to being allowed topass downstream.

WallStent: A Wallstent design may be utilized for treatment of CCSVI. Itis contemplated that the braided design may be optimally suited to thetreatment of a vein due to its good flexibility and its comparativelylow radial strength. By minimizing minimal strength, the likelihood of avascular tear is decreased.

Thombolytics: Thrombolysis may be used to maintain a fluent venoussystem. This process will break down any clots, thrombus, or similartissue that is obstructing the vein using therapeutic agents. Forexample, the infusion of tissue plasminogen activator (tPA) willstimulate fibrinolysis and the dissolution of plaques. After dissolvingthe obstructive tissue, the vein will allow blood flow without causingreflux.

Venous Bypass: It is contemplated that a venous bypass may be used toavoid blood reflux that causes the CCSVI condition. This is a surgicaltechnique in which a vein is grafted across the portion of the vein thatexhibits reflux. By doing so, sufficient blood flow is supported toprevent reflux from persisting and the CCSVI condition is thus treated.

Venous Transplant: In addition to venous bypass, another suitableprocedure is a venous transplant in which the vein is replaced with avein having minimal or no obstructions. Thus, the blood reflux iseliminated in order to treat the CCSVI.

Ultrasonic Disruption: An alternative therapy for opening veinscontributing to CCSVI is the use of ultrasonic disruption. In thisprocedure, an ultrasonic energy source directs energy toward anobstructive tissue either intravascularly or extracorporeally. Theobstruction is thus disrupted and disintegrated in order to open thevein passage and to allow good blood flow without reflux. It may bebeneficial to use a filter in this case.

Micro-Bubble Disruption: Microbubble disruption utilizes the creation ofmicrobubbles in the region of venous obstruction to cause theobstructive tissue to be disrupted and disintegrated, thus opening thevenous passage and preventing reflux. In order to produce themicrobubbles, techniques such as energization of gold microparticles orenergization of micromaterials may be used to cause localized expansionof gases within the blood flow that create bubbles. The bubblessubsequently implode, producing energy that disrupts the adjacent venousobstruction.

Valve Implant: A valve implant may be positioned within the vein thatexhibits reflux in order to prevent the reflux. One type of valve thatis particularly useful for this is a one-way valve, such as a duck-billtype valve. The one-way valve would allow blood to flow in onedirection, but would prevent reflux into the vein when downstreampressure increases.

Each of the therapies discussed above provide an alternative treatmentto stents that avoids the risk of a stent dislodging and causingcomplications within the heart.

While illustrative embodiments of the invention have been disclosedherein, numerous modifications and other embodiments may be devised bythose skilled in the art in accordance with the invention. For example,the various features depicted and described in the embodiments hereincan be altered or combined to obtain desired scaffold characteristics inaccordance with the invention. Therefore, it will be understood that theappended claims are intended to include such modifications andembodiments, which are within the spirit and scope of the presentinvention.

1. A method of deploying a medical device, comprising: establishing anopen condition of a valve in a vessel of a patient; moving a medicaldevice through the opened valve; and deploying the medical device at atarget site, wherein establishing the open condition, moving the medicaldevice and deploying the medical device are completed without negativelyimpacting the function of the valve.
 2. The method of claim 1, whereinestablishing the open condition of the valve includes altering fluidflow through the vessel in the vicinity of the valve.
 3. The method ofclaim 2, wherein altering fluid flow in the vicinity of the valveincludes introducing a fluid in an antegrade direction from a locationupstream of the valve to induce opening of the valve.
 4. The method ofclaim 3, wherein deploying the medical device includes introducing themedical device in a retrograde direction through the opened valve from alocation downstream of the valve.
 5. The method of claim 3, whereinaltering fluid flow in the vicinity of the valve includes occluding thevessel at a location upstream of the valve before introducing the fluid.6. The method of claim 2, wherein altering fluid flow in the vicinity ofthe valve includes drawing fluid flow in an antegrade direction.
 7. Themethod of claim 6, wherein drawing fluid flow in the antegrade directionincludes providing suction at a location downstream of the valve.
 8. Themethod of claim 6, wherein deploying the medical device includesintroducing the medical device in a retrograde direction through theopened valve from a location downstream of the valve.
 9. The method ofclaim 2, wherein altering fluid flow in the vicinity of the valveincludes occluding at least one body lumen proximal to andfluidly-coupled with the vessel to increase antegrade flow across thevalve.
 10. The method of claim 1, wherein establishing the opencondition of the valve includes temporarily expanding an expandable cuffwithin the valve without permanently impacting the function of thevalve.
 11. The method of claim 1, wherein deploying the medical deviceincludes using a catheter, the method further comprising removing thecatheter after deploying the medical device.
 12. The method of claim 1,wherein the medical device is an intraluminal scaffold.
 13. The methodof claim 12, wherein the intraluminal scaffold has a generally tubularbody with a lumen defined therethrough, the tubular body having acompressed condition for delivery and an expanded condition for implantwithin the vessel, at least a length of the tubular body configured toform an enlarged portion in the expanded condition.
 14. The method ofclaim 1, wherein the valve is a venous valve.
 15. The method of claim14, wherein the valve is located in one of an internal jugular vein andan external jugular vein.